mavend: group the recall fields into one wiring struct (V-433)

The review comment asked for basic DI. The answer is the idiom voice.go
already had for capabilities — a cohesive *Wiring struct — applied to a
group that is not a capability toggle, plus the decision written down so
it is a rule and not a habit.

recallWiring holds the embedder, the vector store, the personal boundary
and the two numbers that gate an answer. They sat in three places on
reactiveHandler, with the gate numbers a hundred lines from the store
they gate. Its zero value means no recall, so it is a value, not a
pointer like the optional-capability groups.

dataStore stays out of it. patterns.go, ecosystem_acts.go and confirm.go
use it, so it is not part of this cluster.

docs/handler-wiring.md records the choice, rejects a container or a
wire-style generator outright, defers narrow per-handler interfaces to
the package split that would justify them, and states the constraint the
task named: a wiring change does not ride a feature PR.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cmd/mavend/factgate_test.go

@@ -19,11 +19,10 @@ func newFactGateHandler(t *testing.T, now time.Time) (*reactiveHandler, ipc.Core
 	emb := router.NewHashEmbedder(1024)
 	h := &reactiveHandler{
 		api:       api,
-		embedder:  emb,
+		recall:    recallWiring{embedder: emb, memStore: memory.NewInMemoryStore()},
 		router:    buildRouter(emb, tool.NewMatcher(api), 0.55, nil),
 		replier:   voice.NewStubReplier(),
 		now:       func() time.Time { return now },
-		memStore:  memory.NewInMemoryStore(),
 		dataStore: st,
 	}
 	return h, api
@@ -44,7 +43,7 @@ func TestActionFact_QuestionIsNotWritten(t *testing.T) {
 	if _, err := api.LatestFact(ctx, "go_version"); err == nil {
 		t.Fatal("a question was stored as a fact about him")
 	}
-	hits, err := h.memStore.Search(ctx, mustEmbedPassage(t, h, "какая последняя версия языка Go?"), 3)
+	hits, err := h.recall.memStore.Search(ctx, mustEmbedPassage(t, h, "какая последняя версия языка Go?"), 3)
 	if err != nil {
 		t.Fatalf("memory search: %v", err)
 	}
@@ -81,7 +80,7 @@ func TestActionFact_ExplicitCaptureStillWrites(t *testing.T) {
 	// #493: what recall reads back is the fact, not the sentence he said.
 	// queryMemory returns a fact's text verbatim, so the utterance sitting here
 	// meant "запиши что я пил воду" was the answer to "когда я пил воду?".
-	hits, err := h.memStore.Search(ctx, mustEmbedPassage(t, h, "вода"), 3)
+	hits, err := h.recall.memStore.Search(ctx, mustEmbedPassage(t, h, "вода"), 3)
 	if err != nil {
 		t.Fatalf("memory search: %v", err)
 	}
@@ -117,7 +116,7 @@ func TestFactConfidence(t *testing.T) {
 
 func mustEmbedPassage(t *testing.T, h *reactiveHandler, text string) []float32 {
 	t.Helper()
-	vec, err := router.EmbedQuery(context.Background(), h.embedder, text)
+	vec, err := router.EmbedQuery(context.Background(), h.recall.embedder, text)
 	if err != nil {
 		t.Fatalf("embed %q: %v", text, err)
 	}